A Non-approximated Steady State Model-derived Semiconductor Loss Optimization for Resonant CLLC

Resonant converter modeling performed with resistive approximation of the AC equivalent impedance introduces > 10% error in switching instant value of AC port currents which further propagates in the semiconductor loss calculation yielding incorrect losses during converter operation and inaccuracies in optimum control variables determination required for generating desired power and voltage at the output ports. This paper presents a new modeling approach termed as Improved-Generalized Harmonic Approximation (I-GHA) for resonant converter modeling that accounts for the non-approximated effects of all switching harmonics on determination of the natures of port currents and hence power transfer dynamics. To benchmark the converter performance vis-à-vis the developed analytical model, a wide-bandgap devices-based 2kW- 600-28V hardware prototype is developed and experimented in various operating conditions for a resonant frequency of 500 kHz.